Malaria surveillance reveals parasite relatedness, signatures of selection, and correlates of transmission across Senegal.

We here analyze data from the first year of an ongoing nationwide program of genetic surveillance of Plasmodium falciparum parasites in Senegal. The analysis is based on 1097 samples collected at health facilities during passive malaria case detection in 2019; it provides a baseline for analyzing parasite genetic metrics as they vary over time and geographic space. The study's goal was to identify genetic metrics that were informative about transmission intensity and other aspects of transmission dynamics, focusing on measures of genetic relatedness between parasites. We found the best genetic proxy for local malaria incidence to be the proportion of polygenomic infections (those with multiple genetically distinct parasites), although this relationship broke down at low incidence. The proportion of related parasites was less correlated with incidence while local genetic diversity was uninformative. The type of relatedness could discriminate local transmission patterns: two nearby areas had similarly high fractions of relatives, but one was dominated by clones and the other by outcrossed relatives. Throughout Senegal, 58% of related parasites belonged to a single network of relatives, within which parasites were enriched for shared haplotypes at known and suspected drug resistance loci and at one novel locus, reflective of ongoing selection pressure.

Malaria surveillance reveals parasite relatedness, signatures of selection, and correlates of transmission across Senegal.

Parasite genetic surveillance has the potential to play an important role in malaria control. We describe here an analysis of data from the first year of an ongoing, nationwide program of genetic surveillance of Plasmodium falciparum parasites in Senegal, intended to provide actionable information for malaria control efforts. Looking for a good proxy for local malaria incidence, we found that the best predictor was the proportion of polygenomic infections (those with multiple genetically distinct parasites), although that relationship broke down in very low incidence settings (r = 0.77 overall). The proportion of closely related parasites in a site was more weakly correlated ( r = -0.44) with incidence while the local genetic diversity was uninformative. Study of related parasites indicated their potential for discriminating local transmission patterns: two nearby study areas had similarly high fractions of relatives, but one area was dominated by clones and the other by outcrossed relatives. Throughout the country, 58% of related parasites proved to belong to a single network of relatives, within which parasites were enriched for shared haplotypes at known and suspected drug resistance loci as well as at one novel locus, reflective of ongoing selection pressure.

The use of video job-aids to improve the quality of seasonal malaria chemoprevention delivery.

Mobile phones are increasingly used in community health programmes, but the use of video job-aids that can be displayed on smart phones has not been widely exploited. We investigated the use of video job-aids to support the delivery of seasonal malaria chemoprevention (SMC) in countries in West and Central Africa. The study was prompted by the need for training tools that could be used in a socially distanced manner during the COVID-19 pandemic. Animated videos were developed in English, French, Portuguese, Fula and Hausa, illustrating key steps for administering SMC safely, including wearing masks, washing hands, and social distancing. Through a consultative process with the national malaria programmes of countries using SMC, successive versions of the script and videos were reviewed to ensure accurate and relevant content. Online workshops were held with programme managers to plan how to use the videos in SMC staff training and supervision, and the use of the videos was evaluated in Guinea through focus groups and in-depth interviews with drug distributors and other staff involved in SMC delivery and through direct observations of SMC administration. Programme managers found the videos useful as they reinforce messages, can be viewed at any time and repeatedly, and when used during training sessions, provide a focus of discussion and support for trainers and help retain messages. Managers requested that local specificities of SMC delivery in their setting be included in tailored versions of the video for their country, and videos were required to be narrated in a variety of local languages. In Guinea, SMC drug distributors found the video covered the all the essential steps and found the video easy to understand. However, not all key messages were followed as some of the safety measures, social distancing and wearing masks, were perceived by some as creating mistrust amongst communities. Video job-aids can potentially provide an efficient means of reaching large numbers of drug distributors with guidance for safe and effective distribution of SMC. Not all distributors use android phones, but SMC programmes are increasingly providing drug distributors with android devices to track delivery, and personal ownership of smartphones in sub-Saharan Africa is growing. The use of video job-aids for community health workers to improve the quality delivery of SMC, or of other primary health care interventions, should be more widely evaluated.

Proactive community case management in Senegal 2014-2016: a case study in maximizing the impact of community case management of malaria.

The Senegal National Malaria Control Programme (NMCP) introduced home-based malaria management for all ages, with diagnosis by rapid diagnostic test (RDT) and treatment with artemisinin-based combination therapy (ACT) in 2008, expanding to over 2000 villages nationwide by 2014. With prise en charge à domicile (PECADOM), community health workers (CHWs) were available for community members to seek care, but did not actively visit households to find cases. A trial of a proactive model (PECADOM Plus), in which CHWs visited all households in their village weekly during transmission season to identify fever cases and offer case management, in addition to availability during the week for home-based management, found that CHWs detected and treated more cases in intervention villages, while the number of cases detected weekly decreased over the transmission season. The NMCP scaled PECADOM Plus to three districts in 2014 (132 villages), to a total of six districts in 2015 (246 villages), and to a total of 16 districts in 2016 (708 villages). A narrative case study with programmatic results is presented. During active sweeps over approximately 20 weeks, CHWs tested a mean of 77 patients per CHW in 2014, 89 patients per CHW in 2015, and 90 patients per CHW in 2016, and diagnosed a mean of 61, 61 and 43 patients with malaria per CHW in 2014, 2015 and 2016, respectively. The number of patients who sought care between sweeps increased, with a 104% increase in the number of RDTs performed and a 77% increase in the number of positive tests and patients treated with ACT during passive case detection. While the number of CHWs increased 7%, the number of patients receiving an RDT increased by 307% and the number of malaria cases detected and treated by CHWs increased 274%, from the year prior to PECADOM Plus introduction to its first year of implementation. Based on these results, approximately 700 additional CHWs in 24 new districts were added in 2017. This case study describes the process, results and lessons learned from Senegal's implementation of PECADOM Plus, as well as guidance for other programmes considering introduction of this innovative strategy.

Assessment of the utility of a symptom-based algorithm for identifying febrile patients for malaria diagnostic testing in Senegal.

BACKGROUND: Malaria rapid diagnostic tests (RDTs) enable point-of-care testing to be nearly as sensitive and specific as reference microscopy. The Senegal National Malaria Control Programme introduced RDTs in 2007, along with a case management algorithm for uncomplicated febrile illness, in which the first step stipulates that if a febrile patient of any age has symptoms indicative of febrile illness other than malaria (e.g., cough or rash), they would not be tested for malaria, but treated for the apparent illness and receive an RDT for malaria only if they returned in 48 h without improvement. METHODS: A year-long study in 16 health posts was conducted to determine the algorithm's capacity to identify patients with Plasmodium falciparum infection identifiable by RDT. Health post personnel enrolled patients of all ages with fever (≥37.5 °C) or history of fever in the previous 2 days. After clinical assessment, a nurse staffing the health post determined whether a patient should receive an RDT according to the diagnostic algorithm, but performed an RDT for all enrolled patients. RESULTS: Over 1 year, 6039 patients were enrolled and 58% (3483) were determined to require an RDT according to the algorithm. Overall, 23% (1373/6039) had a positive RDT, 34% (1130/3376) during rainy season and 9% (243/2661) during dry season. The first step of the algorithm identified only 78% of patients with a positive RDT, varying by transmission season (rainy 80%, dry 70%), malaria transmission zone (high 75%, low 95%), and age group (under 5 years 68%, 5 years and older 84%). CONCLUSIONS: In all but the lowest malaria transmission zone, use of the algorithm excludes an unacceptably large proportion of patients with malaria from receiving an RDT at their first visit, denying them timely diagnosis and treatment. While the algorithm was adopted within a context of malaria control and scarce resources, with the goal of treating patients with symptomatic malaria, Senegal has now adopted a policy of universal diagnosis of patients with fever or history of fever. In addition, in the current context of malaria elimination, the paradigm of case management needs to shift towards the identification and treatment of all patients with malaria infection.

Reduction in symptomatic malaria prevalence through proactive community treatment in rural Senegal.

OBJECTIVES: We piloted a community-based proactive malaria case detection model in rural Senegal to evaluate whether this model can increase testing and treatment and reduce prevalence of symptomatic malaria in target communities. METHODS: Home care providers conducted weekly sweeps of every household in their village throughout the transmission season to identify patients with symptoms of malaria, perform rapid diagnostic tests (RDT) on symptomatic patients and provide treatment for positive cases. The model was implemented in 15 villages from July to November 2013, the high transmission season. Fifteen comparison villages were chosen from those implementing Senegal's original, passive model of community case management of malaria. Three sweeps were conducted in the comparison villages to compare prevalence of symptomatic malaria using difference in differences analysis. RESULTS: At baseline, prevalence of symptomatic malaria confirmed by RDT for all symptomatic individuals found during sweeps was similar in both sets of villages (P = 0.79). At end line, prevalence was 16 times higher in the comparison villages than in the intervention villages (P = 0.003). Adjusting for potential confounders, the intervention was associated with a 30-fold reduction in odds of symptomatic malaria in the intervention villages (AOR = 0.033; 95% CI: 0.017, 0.065). Treatment seeking also increased in the intervention villages, with 57% of consultations by home care providers conducted between sweeps through routine community case management. CONCLUSIONS: This pilot study suggests that community-based proactive case detection reduces symptomatic malaria prevalence, likely through more timely case management and improved care seeking behaviour. A randomised controlled trial is needed to further evaluate the impact of this model.